Ground effect machines

ABSTRACT

1,003,211. Air cushion vehicles. WESTLAND AIRCRAFT Ltd. Nov. 13, 1962 [Nov. 21, 1961], No. 41543/61. Heading B7K. An air cushion vehicle has a rigid base provided with flexible downwardly extending skirting or air trunking which may be retracted so that the vehicle can be used as a boat, or lowered on to a hard standing, by drawing the free or lower edge thereof towards the base so as to be distorted in a predetermined manner from its shape when extended, avoiding indiscriminate crumpling. Fig. 1 shows a section through an annular trunking 5 attached to a rigid buoyancy platform 3 and the outer wall 1 of a peripheral curtain-forming duct 4. The trunking is composed of outer and inner annular walls 6, 7, of rubber, rubberized fabric, or plastic, releasably attached to wall 1 and platform 3 by hinge and drawpin assemblies 9 (see also Fig. 3). Shaping and strengthening diaphragms 18, 19 connect the walls 6, 7, and impart a rearward component of velocity to the air in the curtain to effect propulsion (see Fig. 2). Cables 15 within the duct 4 are attached to wall 7 at points 17 by inverted Y ties 16. When the cables are pulled, the trunking assumes the section shown in broken lines in Fig. 1, with folding of wall 7 at 13. Where the periphery is curved, as is seen in Fig. 3, the trunking must contract in the peripheral sense, and the ties 16 effect contraction of alternate sections 12 as at 14, sections 11 remaining taut. Cork blocks 21 maintain the nozzles close to the water surface so that a cushion is formed correctly when the vehicle is to rise from the water after use as a boat. Flexible stabilizing keels may be similarly retracted.

March 29, 1966 R, s. JONES ETAL 3,243,005 GROUND EFFECT MACHINES A Filed NOV. 9, 1962 INVENTORS RICHARD STANTON JONES NORMAN RALPH TAYLOR ATTORNEYS United States Patent O 3,243,005 GROUND EFFECT MACHINES Richard S. Jones and Norman Ralph Taylor, Cowes, Isle of Wight, England, assigner-s to Westland Aircraft Limited, Yeovil, England Filed Nov. 9, 1962, Ser. No. 236,673 Claims priority, application Great Britain, Nov. 21, 1961, 41,543/ 61 Claims. (Cl. 180--7) This `invention relates to ground effect vehicles and more particularly to ground-effect vehicles using peripheral annular jets to generate and retain the pressurized air cushion upon which the vehicle rides,

Experience has shown that vehicles of this type are more efficient and more stable, especially at maximum cushion height, if the lift jets and/ or stability jets are flexibly extended from the rigid base structure to a predetermined depth beneath the vehicle. However this method of improving the performance of the vehicle in some of its operating roles is a considerable hindrance in others. For example, when a buoyant ground-effect vehicle, that is to say a vehicle which will oat on water when unsupported by a ground-effect pressurized air cushion, is used as a boat, the presence of the inert flexible air trunking immersed in the water, causes considerable drag which retards lboth propulsion and maneuverability. Also, when the air supply to the lift jets is cut off and the machine alights on a solid surface, indiscriminate crumpling of the exible skirts and/ or `air trunking under the weight of the vehicle can cause considerable damage to the liexible portions.

One object of the present invention is to provide an arrangement which permits peripheral skirting or trunking lto be retracted in a comparatively simple manner in order to reduce or even entirely overcome the problems outlined above.

It is now established that the maximum benets accrue from the use of ilexible extensions when they form flexible air trunks or ducts continuing both walls of the pressure air jets from the rigid base structure of the vehicle to an air discharge point below it. With all such arrangements it is in general, necessary to restrain unwanted deflections of the complete trunk and those parts forming the air channels. This complicates the problem of retraction by the necessary presence of ties and/-or shape maintaining diaphragms which must not be damaged and which limit the ilexibility of movement in certain directions.

The invention consists in a ground-effect vehicle of the kind set forth in which the rigid base structure is provided with ilexible downwardly-extending skirting of air trunking which is retractable 'by drawing the free or lower edge towards the rigid base structure in such a manner that the skirt or trunk is caused to assume a predetermined pattern of distortion from its inherent shape, avoiding indiscriminate crumpling, when moved into the retracted position, but will return to the normal inherent shape when re-extended.

Other objects and advantages of the invention will become apparent from the following detailed description with reference to the accompanying drawings in which:

FIGURE 1 is a section through the peripheral annular Patented Mar. 29, 1966 ICC duct of a ground-effect vehicle substantially on the line I-I of FIG. 2 showing the flexible trunking in the extended position, and the retracted position is shown dotted.

FIGURE 2 is a side elevation of trunking itted with the `invention as Viewed on arrow II of FIGURE 1.

FIGURE 3 is a perspective view from beneath the Vehicle on arrow III of FIGURE l showing a portion of the -trunking in the retracted position.

One embodiment of the inventionwill now be described which is by way of example with reference to the accompanying drawings.

Referring to the drawings, like numerals represent like part-s in which 1 indicates the solid outer wall of a peripheral duct 4, 2 in the solid inner wall of peripheral duct 4, which is also part of the main platform or buoyancy tank 3. Attached to the walls 1 and 2 of the peripheral duct 4 and extending same to thek required depth beneath the lsolid structure is a flexible trunking generally indicated at 5, which may be of fabric, rubber, rubberized fabric, plastic or any similar material. The trunking comprises a flexible -outer skirt 6 and a flexible inner skirt 7 which are joined at spaced intervals by srtengthening and shaping ties or di-aphragms 18 and 19 to form integral portions which may be fitted t-o the peripheral duc-t of the Vehicle in any suitable lengths and joined together Ito form fluid tight joints.

The upper edges of the flexible trunking 5 are fastened to the rigid base structure 1 and 2 of the vehicle in alignment with the air ducts, by detachable fastenings such as hinge and drawpin larrangements or the like. This arrangement has the advantage that the fastening forms a natural hinge point as indicated at 9 which enables the lower free edge of the trunk 5 to be drawn inwardly to lie within the plan area of the rigid base when retracted. Deformation or distortion into the predetermined pattern which will avoid indiscriminate crumpling of the flexible material is made by disposing the retractive points 10 at suitably spaced intervals along the trunking so that alternative spans lbetween pairs of retracting points are respectively maintained in substantially rigid and collapsed conditions when retracted as indicated at 11 and 12 in FIGURE 2. This arrangement ensures that the decreased area available in which the trunk 5 must lie under the base when retracted is allowed for in the folds 13 inthe upper portion of the inner skirt 7, as seen in FIGURES 1 and 3, and folds 14 which will take place in the inner and outer skirt 6 and 7. In this construction the retractive pull is conveniently provided by cables 15 one of which is associated with each retraction point 10 along the trunk 5. Each cable 15 is divided at the end adjacent Ithe trunk 5 into inverted Y arms 16, which are separately attached to the trunk at convenient points 17 onA the inner skirt. Thus it will be seen that the attachment points 17 are provided on the ends of the long diaphragms 18 which are natural strong points on the flexible structure 5.

In this way, when the tails 15 of the inverted Y cables 16 are pulled simultaneously to retract the trunk 5 the adjacent Y arms 16 of each pair .of retraction cables 15,

exerts, in addition to an upward pull, a side pull which maintains the trunk span 11 between the cables tau-t, whilst the span 12 between the inverted Y arms 16 of each cable 15 is subjected to an inward pull in addition to an upward pull thereby urging the span 12 to collapse outwardly as retraction takes place. In this construction the invention is applied to the peripheral trunking of a peripheral annular jet type vehicle in which the upper portion is angled inwardly towards the buoyancy tank 3, and the point 17 where the angled upper part joins the more nearly vertical lower portion of the inner skirt 7 is a convenient point for attaching the retraction cables 16 to the trunk 5. In this installation the retraction cables 15 and 16 are located within the trunk 5 and are operated by actuators (not shown) located within the air duct 4 of the rigid structure, the cables passing over pulleys (not shown) where necessary in the manner of aircraft control cables and terminating at a suitable control lever or switch disposed within the cockpit of the vehicle. This arrangement has the advantage that the retraction gear is protected to a large extent from oorrosion by location within an environment which is comparatively free from water spray and is also protected from wave impact.

When applied to peripheral trunking as in the example illustrated, the transversely disposed long diaphragms 18 and the short diaphragms 19 may be angled aft, so that the nozzles 20 formed in the main trunking 5 by the diaphragms 18 and 19 cause their air to be discharged rearwards as well as inwards in 4order to assist propulsion in addition to generating the pressurized cushion. This also has the effect of reducing resistance to retraction of the trunks since the shortening of the diaphragm has not got to be so great.

The embodiment of the invention hereinbefore described is consistant with substantially straight lengths of ducting more applicable to the sides of the vehicle. However, when installed at the rounded bow or stern it will be obvious that certain minor complications Will arise in that the folding of the flexible material will not be equal to that along the straight sections. This difculty can be overcome by manufacturing the trunking for a rounded bow or stern in segmented sections adapted to the curve and catering for slightly modied fold lines which will taper towards the centre of the vehicle.

' In operation of the invention, when boating or water taxiing is necessary the pilot will operate a switch in the cockpit which will cut in electric or hydraulic actuators which will operate to shorten the control cables 15 by winding them in round a spool or the like or alternatively by direct pull from a control lever. This will initiate the sequence of retraction of the trunking with controlled folding, as hereinbefore described, by drawing the trunking upwards and inwards to lie under the rigid base structure 3 as indicated by the dotted lines in FIGURE 1 and in FIGURE 3. The lower inner edge of the trunk 5 may be provided with buoyant material such as cork blocks 21 in order to maintain the jet orifices close to the surface of the water. This ensures that they are correctly directed to generate the pressurized air cushion under the base of the vehicle when it is required to rise from the water after use as a boat. Re-extension of the trunking after retraction is eiected by the internal inflationary action of the pressure air in the nozzles 20 assisted by the static weight of the trunk 5. Similarly, retraction could take place before touch down on a hard standing in order to minimize damage to the flexible portions.

It will also be understood by those skilled in the art that other embodiments are possible without departing from the scope of the invention in that flexible stability keels, sidewalls and like portions could be retracted in a similar manner if desired.

We claim as our invention:

1. In a ground effect vehicle, a rigid base structure, means for directing pressurized fluid under said base structure to form 4a pressurized fluid supporting cushion, a flexible skirting member attached to and extending downwardly from substantially the periphery of said rigid base structure to a level below the lowest point of thel rigid base structure when extended for assisting in the maintenance of said pressurized fluid supporting cushion, a series of longitudinally spaced retraction points extending along said ilexible skirting member, and means for lifting said flexible skirting member upwardly and inwardly under said base structure and for urging at least some of said retraction points toward an adjacent retraction point to form predetermined fold-like distortions between retraction points and extending toward the lower edge of said exible skirting member from its line of attachment to said rigid base structure.

2. Apparatus as recited in claim 1 wherein said lastmentioned means comprises a plurality of retraction members attached to said exible skirting member at said retraction points, at least some of adjacent ones of said retraction members being directed to urge their respective retraction points toward each other.

3. Apparatus as recited in claim 1 wherein said lastmentioned means comprises a plurality of exible retraction members having inverted Y shaped ends, the lower legs of said Y shaped ends being attached to spaced retraction points.

4. Apparatus as set forth in claim 3 wherein adjacent ones of said flexible retraction members are spaced from each other to provide a span of flexible skirting between adjacent lower legs of adjacent retraction members, whereby said spans will be placed under tension upon retraction of said flexible skirting member, and the portions of said exible skirting member between the Y shaped legs of individual llexible retracting members will be substantially free of tension so as to permit said portions to fold upon themselves as retraction takes place.

5. In a ground effect vehicle, a rigid base structure, means forming a downwardly directed duct substantially around the periphery of said rigid base structure, a flexible skirting member having inner and outer walls attached to said rigid base structure and extending downwardly therefrom to form a continuation of said downwardly directed peripheral duct, said flexible skirting member being open at its lower edge so as to permit pressurized Huid to pass from said duct downwardly to be discharged from said flexible skirting member at the lower edge thereof, and means for lifting said exible skirting member inwardly and upwardly under said base structure and for urging spaced portions of said exible skirting member to form predetermined fold-like distortions extending toward the lower edge of said flexible skirting member from its line of attachment to said rigid base structure as said member is retracted upwardly.

6. Apparatus as recited in claim 5 wherein said lastmentioned means comprises a plurality of retraction members attached to said exible skirting member at a series of retraction points spaced longitudinally along said member, at least some of adjacent ones of said retraction members being directed to urge their respective retraction points toward each other.

7. Apparatus as recited in claim 5 wherein said lastmentioned means comprises a plurality of flexible retraction members having inverted Y shaped ends, the lower legs of said Y shaped ends being attached to spaced retraction points.

8. Apparatus as set forth in claim 7 wherein adjacent ones of said exible retraction members are spaced from each other to provide a span of flexible skirting between adjacent lower legs of adjacent retraction members, whereby said spans will be placed under tension upon retraction of said flexible skirting member, and the portions of said exible skirting member between the Y shaped legs of individual exible retracting members will be substantially free of tension so as to permit said portions to fold upon themselves as retraction takes place.

9. Apparatus as recited in claim 8 further comprising a plurality of exible members extending generally downwardly and connecting said inner and outer spaced wall of said flexible skirting member, the lower legs of said Y shaped ends being attached to said flexible skrtng member at the upper edges of said plurality of iiexible members.

10. Apparatus as set forth in claim 9 wherein said flexible retraction members pass downwardly through said duct for attachment to said flexible skirting member.

References Cited by the Examiner UNITED STATES PATENTS Porter 180-7 Nicin 180-7 Brown 180-7 Priest 180-7 Griith 180-7 0 MILTON BUCHLER, Primary Examiner.

LEO FRIAGLIA, Examiner. 

1. IN A GROUND EFFECT VEHICLE, ARIGID BASE STRUCTURE, MEANS FOR DIRECTING PRESSURIZED FLUID UNDER SAID BASE STRUCTURE TO FORM A PRESSURIZED FLUID SUPPORTING CUSHION, A FLEXIBLE SKIRTING MEMBER ATTACHED TO AND EXTENDING DOWNWARDLY FROM SUBSTANTIALLY THE PERIPHERY OF SAID RIGID BASE STRUCTURE TO A LEVEL BELOW THE LOWEST POINT OF THE RIGID BASE STRUCTURE WHEN EXTENDED FOR ASSISTING IN THE MAINTENANCE OF SAID PRESSURIZED FLUID SUPPORTING CUSHION, A SERIES OF LONGITUDINALLY SPACED RETRACTION POINTS EXTENDING ALONG SAID FLEXIBLE SKIRTING MEMBER, AND MEANS FOR LIFTING SAID FLEXIBLE SKIRTING MEMBER UPWARDLY AND INWARDLY UNDER SAID BASE STRUCTURE AND FOR URGING AT LEAST SOME OF SAID RECTRACTION POINTS TOWARD AN ADJACENT RETRACTION POINT TO FORM PREDETERMINED FOLD-LIKE DISTORTIONS BETWEEN RETRACTION POINTS AND EXTENDING TOWARD THE LOWER EDGE OF SAID FLEXIBLE SKIRTING MEMBER FROM ITS LINE OF ATTACHMENT TO SAID RIGID BASE STRUCTURE. 